Call the OHM and ask them (in English) where to send the money. The phone number is on the website:
Here's the number:
+33 (0) 4 50 53 22 08
If you're calling from the US, dial 011 0033 4 50 53 22 08
Note also that you must send a certified bank check...go to your bank to get one. Personal checks from the US are of no value to Europeans.